Some trainees rely on target heart rate, determined in an all-out exercise test performed once a season, for setting their training program. Other trainees rely on estimated target heart rate, usually based on a prediction formula or a coach's assessment, for setting their training program.
However, it is not uncommon during certain days to begin an aerobic practice feeling terrific, only to be limited by a pulse tracking device which doesn't stop beeping when that activity is sustained beyond the comfort zone kept in the pulse tracking device. Alternatively, it is not uncommon during certain days to have a ‘bad day’ in which it is too strenuous to practice within the comfort zone kept in the pulse tracking device.
At sub-ventilatory threshold activity levels, when energy consumption and ventilation are less than at the ventilatory threshold, the user's aerobic metabolism sustains physical effort for the most part. Such activity levels can therefore be sustained for extended periods of time. For example, long distance runners aim for such activity levels for most of a marathon. At supra ventilatory threshold activity levels, when energy consumption and ventilation are greater than at the ventilatory threshold, the user's aerobic metabolism is complemented by anaerobic metabolism to a degree that will cause cessation of exercise before long, most probably due to accumulation of anaerobic metabolism by-products. It is to be noted that for most clinical and practical purposes, the ventilatory threshold is equated here with the anaerobic threshold, which, for the same purposes, is on a par with the blood lactate threshold.
When a patient is in the recovery stage from a heart or lung disease, especially in the case of rehabilitation using a training device, training itself could be dangerous for the patient if it is carried out without correctly assessing the variations in his/her physical conditions, which occur from time to time.
The talk test is a well-known method for assessing the current heart rate training zone that corresponds to the user's ventilatory threshold. One talk test example includes the following stages:
In the first stages of exercise, the user can breathe deeply in a timely manner, accommodating both the fluency of his/her conversation and the increasing needs of respiration.
In a further stage, as pace is maintained, and the user resumes talking towards the end of the stage, it may become apparent to the human ear that a few long sentences (such as over 10 words, or linked sentences with more than one clause) are interspersed with shorter sentences. A user may further modify his/her diction, or choice of words, for example by first expressing his/her feeling in “yes, as you can see I am doing quite nicely”, to be followed by the more condensed form of speech “you see?! I'm fine!”. Alternatively, a user may be prone to squeezing out the last words in every sentence, varying his/her pitch, as well as uttering words more quickly.
Inhalations change in quality as the test progresses. In between sentences uttered, or lines of a song or recited paragraph, or hummed tunes of a musical piece, inhalations become deeper as a manifestation of hyperpnea.
A consistent observation made during this further stage, usually used to infer exceeding the “ventilatory threshold zone”, is of interruptions constituting, in addition to deeper inhalations in between sentences, pauses in the middle of some sentences. If during these interruptions a labored pattern of inhalation takes place, then the ventilatory threshold has been reached or exceeded.
Continuing the test may serve as validation. As effort continues to increase, interruptions in even short sentences or recitation pieces become regular and unavoidable. However, this stage is most often interpreted as exceeding the bounds corresponding to the ventilatory threshold.
Optionally, the ventilatory threshold is reached when the voice produced by the user whether singing, whistling, or humming, begins to break down into pauses (for inspiration) which are discordant with the breaks or softer notes in the melody. Alternatively or additionally, the ventilatory threshold is reached when the user's voice significantly changes its pattern.
In some cases, the talk test is performed with a psychophysiological scale, such as the Rate of Perceived Exertion (RPE) test. The level of perceived exertion may be assessed with almost any category scale such as:
A) The Borg scale that includes the rates: 6—No exertion at all, 7—Extremely light exertion, 8, 9—Very light exertion, 10, 11—Light exertion, 12, 13—Somewhat hard, 14, 15—Hard (heavy), 16, 17, 18, 19—Extremely hard, and 20—Maximal exertion.
B) An RPE scale that includes: Moderate Zone: RPE 4-5 (approximately 50% of maximum heart rate); RPE 6-7 (approximately 60-70% of maximum heart rate); RPE 7-8 (approximately 70-80% of maximum heart rate); and RPE 8-10 (approximately 80-100% of maximum heart rate).
C) An RPE scale that includes: 1—No exertion at all, 2—Very light exertion, 3—Light exertion, 4, 5—Somewhat hard, 6, 7—Hard (heavy), 8, 8.5—Very hard, 9, 9.5—Extremely hard, and 10—Maximal exertion.
In some cases, training programs are based on one or more of the following parameters: target heart rate, heart rate training zone, anaerobic threshold, ventilatory threshold, intensity factor, adjuster factor, or the maximum estimated target heart rate. However, these parameters may be influenced by environmental conditions, the user's physiological condition, and/or the user's psychological condition. FIG. 8A and FIG. 8B illustrate some problems related to setting the target heart rate.